Lifestyle factors have been demonstrated to contribute significantly to coronary heart disease (CHD) risk. A major challenge is to develop long-term approaches that favorably modify these behaviors, particularly in populations at increased risk. The current project is being conducted to evaluate the effects of several physical activity regimens on selected CHD risk factors in men and women ages 50-64 years. In addition to comparing the effects of lower versus higher intensity exercise on biologic and psychologic measures, the effectiveness of a home-based model of exercise training is being compared to a more standard instructor- led class program. A health/activity interview was performed by 2328 residents of the city of Sunnyvale of which 357 were randomized to one of 3 exercise training regimens or control. Evaluations are repeated every 6 months for 2 years. Measurements include lipoproteins, insulin, sex hormones, blood pressure, adiposity, endurance capacity, smoking, dietary activity behaviors, type A-B behavior, and measures of anxiety, depression, and quality of life. The study is in progress with all subjects having completed between 6 and 18 months. Adherence to the exercise regimens exceeded 72% during the first 6 months and 70% for subjects completing one year. This application proposes to follow these subjects for a total of 3 years. It is likely that exercise combined with diet would have a greater impact on reducing CHD risk than exercise or diet alone. Therefore, a new study is proposed that is designed to test the effectiveness of optimally combining exercise and a low fat diet regimen, using a class- versus a home-based model, in favorably modifying CHD risk factors. Recruitment will take advantage of the previously identified community-based sample. Men age 50-69 years (N=260)at increased risk of CHD will be randomized following a baseline evaluation to either class-based exercise plus diet, home- based exercise plus diet, home-based diet alone or control. Regimens will be individually prescribed and will include monitoring, support, and feedback to maintain adherence. Major outcomes include changes in lipoproteins, apoproteins, glucose and insulin, blood pressure, adiposity, fibrinogen and aerobic capacity. Measurements will be repeated at 6 and 12 months. The innovative programs being proposed take advantage of the potential synergy between exercise and a low fat diet and should result in more powerful and diverse approaches to risk reduction in men at increased risk.